AMR Sensor Linearity via Segmented Resistive Strip

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Solution Overview

Problem

Conventional anisotropic-magnetoresistive (AMR) sensors exhibit non-linear magnetic field responses due to the uniform width and single angle configuration of conductive strips, limiting their effectiveness in accurately sensing magnetic fields.

Innovation Solution

The AMR sensor design incorporates multiple sections of different constant widths with conductive strips oriented at varying angles, allowing for a superimposed positive and negative slope response to achieve a highly linear magnetic field detection, facilitating enhanced linearity and ease of magnetization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional AMR sensors use uniform width and single angle configuration of conductive strips, then the sensor structure is simple, but the magnetic field response is non-linear

Engineering Contradiction:
Improvelinearity of magnetic field responseVSAvoidsensor structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The resistive strip is divided into multiple sections with different constant widths (first section, second section, third section). Each section has conductive strips oriented at different angles, creating segmented functional regions that collectively achieve linear magnetic field response through their combined characteristics.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the resistive strip are given different local properties: varying widths and different conductive strip orientations. The first section has conductive strips at a first angle, the second section has conductive strips at a second angle, and the third section has conductive strips at a third angle, optimizing each local region's contribution to the overall linear response.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If multiple sections with different widths and angles are used, then linearity is improved, but the sensor design becomes more complex

Engineering Contradiction:
Improvemagnetic field sensing accuracyVSAvoidsensor design complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor is segmented into multiple functional sections along the resistive strip, with each section contributing differently to the magnetic field response. This segmentation allows precise control over the overall response characteristics while maintaining a relatively simple integrated structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The resistive strip serves multiple functions simultaneously: it provides the AMR sensing element, acts as a current path, and through its segmented structure with varying widths and orientations, creates multiple sensing zones with different response characteristics that combine to achieve linearization.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If conductive strips are oriented at varying angles in different sections, then linear response is achieved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvelinearity of responseVSAvoidease of manufacturing
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Each section of the resistive strip is optimized with specific local qualities including constant width and specific conductive strip orientations. The first section has a first constant width with conductive strips at a first angle, the second section has a second constant width with conductive strips at a second angle, and the third section has a third constant width with conductive strips at a third angle, allowing precise control of magnetic response in each region.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design results in a significantly improved linear magnetic field response over a wide range, enabling more accurate sensing and easier magnetization, as demonstrated by the superimposed response curves in the patent description.

Implementation Method 1

Anisotropic-magnetoresistive (AMR) sensors are used to sense magnetic fields by detecting a change in resistance of the sensor as a result of the magnetic field

Methodology Applied
Scientific EffectAnisotropic magnetoresistance: Magnetoresistance

Implementation Method 2

conductive strips on a wider section of the resistive strip may be at an opposite angle relative to the conductive strips on a narrower section

Methodology Applied
Scientific EffectMagnetization rotation: Magnetic Field

Data Source

PatentEP3889629B1AMR (XMR) sensor with increased linear range
Publication Date: 2024.03.20 ANALOG DEVICES INT UNLTD CO
  • EP3889629B1 patent drawingFigure 1~2
  • EP3889629B1 patent drawingFigure 3A~3B
  • EP3889629B1 patent drawingFigure 4

AI summary

Anisotropic-magnetoresistive (AMR) sensors are described. The AMR sensors have a barber pole structure with multiple constant width sections of different width. In some embodiments, two sections of greater, constant width are positioned at ends of the AMR sensor, with a section of smaller width positioned in between. The sections of greater width may have a total length less than the section of smaller width. The structures described may provide enhanced linearity.